#include<iostream>
#include<vector>

using namespace std;

bool cmp(vector<int> A,vector<int> B){//A>=B
	if(A.size() !=B.size() ){
		return A.size()>B.size();
	}else{
			for(int i=A.size() -1;i>=0;i--){
		if(A[i]!=B[i]){
			return A[i]>B[i];
		}
	}
	}

	return true;
}

vector<int> sub(vector<int> A,vector<int> B){
	vector<int> C;
	int t=0,i=0;
	for(i=0;i<A.size() ;i++){
		t=A[i]-B[i]-t;
		C.push_back((t+10)%10);
		if(t<0){
			t=1;
		} else{
			t=0;
		}
	}
	while(C.size() >1&&C.back() ==0){
		C.pop_back() ;
	}
	return C;
}

int main(){
	int i=0;
	string a,b;
	vector<int> A,B;
	cin>>a>>b;
	for(i=a.size() -1;i>=0;i--){
		A.push_back(a[i]-'0'); 
	}
	for(i=b.size() -1;i>=0;i--){
		B.push_back(b[i]-'0'); 
	}
	if(cmp(A,B)){
		vector<int> C=sub(A,B);
			for(i=C.size() -1;i>=0;i--){
		cout<<C[i];
	}
	}else{
		vector<int> C=sub(B,A);
		cout<<'-';
			for(i=C.size() -1;i>=0;i--){
		cout<<C[i];
	}
	}

	return 0;
} 
